Prince William has revealed it's taken him 20 years to get over the death of his mother Princess Diana.

In the new issue of GQ as part of the ongoing Heads Together campaign, HRH The Duke of Cambridge spoke about the upcoming 20th anniversary of the sudden death of Diana in 1997.

"I am in a better place about it than I have been for a long time, where I can talk about her more openly, talk about her more honestly, and I can remember her better, and publicly talk about her better," he reflected.

"It has taken me almost 20 years to get to that stage. I still find it difficult now because at the time it was so raw. And also it is not like most people's grief, because everyone else knows about it, everyone knows the story, everyone knows her.

"It is a different situation for most people who lose someone they love – it can be hidden away or they can choose if they want to share their story."

Father-of-two William also noted how he wished his mother was still around today to meet his wife, the Duchess of Cambridge, and their children.

"I would like to have had her advice. I would love her to have met Catherine and to have seen the children grow up. It makes me sad that she won't, that they will never know her," he explained.